The need for a new breed of business representative arose from the long history of authors' poverty and their apparent inability to help themselves. In
The Vanity of Human Wishes (1748), Samuel Johnson asked his readers to "mark what ills the scholar's life assail: toil, envy, want, the patron, and the jail."

The need for a new breed of business representative arose from the long history of authors' poverty and their apparent inability to help themselves. In The Vanity of Human Wishes (1748), Samuel Johnson asked his readers to "mark what ills the scholar's life assail: toil, envy, want, the patron, and the jail."

Among most publishers, AP Watt was not popular. If, as authors maintained, Barabbas was a publisher, then the new mercenary agent was, according to publishers, an unrepentant thief. William Heinemann described him as a parasitical middleman of dubious honesty who flourished without qualifications and destroyed the "intimate intercourse between author and publisher".

Watt's clients included Wilkie Collins, Conan Doyle, Thomas Hardy and Rudyard Kipling. But not all writers thought well of him. Conrad likened his soliciting testimonials to the credentials of a Malayan laundryman. Henry James used him briefly because "he appeared eager to undertake me, and I am promised remarkable good results. He takes 10 per cent of what he gets for me, but I am advised that his favourable action more than makes up for this."

Unfortunately it didn't, and Henry James soon turned instead to JB Pinker - a short, compact, round-faced, dapper sphinx of a man who laughed without facial movement and spoke in a hoarse whisper. Pinker was the other great authors' valet of these early years. By the early 20th century he looked after Arnold Bennett and HG Wells, as well as Henry James and Joseph Conrad.

Between the two world wars, though guerrilla activity between agents, authors and publishers persisted, the question of whether a writer should employ an agent was generally settled. Most writers now felt the "relief and comfort" that Henry James had described at having an agent "take all the mercenary and selling side off one's mind".

When I began writing in the late 1950s, I was advised to go to an agent by the Society of Authors. My relationship with AP Watt during the 1960s and 1970s plotted a sensible if unsensational course for me that did not vex publishers too much or come to the notice of the general public. But towards the end of the 1980s, this dramatically changed. For my multi-volume biography of Bernard Shaw, Hilary Rubinstein at AP Watt secured me an advance on royalties of £625,000.

In fact, this lump sum was to be paid to me over a dozen years, and was in effect a middle-age pension of some £40,000 a year which freed me from journalism and lecturing. Writers, on the whole, do not write books for money, but spend money buying time to write books.

I was described in some newspapers as a lottery winner, and in others depicted as an obscenely greedy capitalist who was stealing money from my fellow authors. My post was full of begging and threatening letters, and I became the Martin Amis or Amy Jenkins of the day.

This experience illustrates the great change that has come over the world of books. In the modern competitive publishing industry, no author seems safe without the protection of an agent. Agents now are famous - Andrew Wylie is almost as newsworthy as his star client, Salman Rushdie.

But some things have not changed so much. "Toil, envy, want, the patron and the jail." The toil of writing is much the same as it ever was. The want is still there. Despite what you read about the occasional fabulous advance, many writers are obliged to seek help from the Authors' Foundation, a charity run by the Society of Authors to help writers finish their books. Authors' incomes are so erratic that they do not usually have adequate pensions. But thanks to the Royal Literary Fund, which has benefited fantastically from Disney's exploitation of Winnie-the-Pooh, they are no longer heading for the jail.